All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Enhanced Pedon Horizonation Using Portable X-ray Fluorescence SpectrometryPedology M any soils feature well-developed, easily recognizable genetic horizons formed as a result of advanced pedogenesis. In Louisiana, alluvium is extensive given the numerous river systems (Mississippi, Red, Pearl, Sabine) that have periodically fl ooded the state for centuries. Modest topographic relief in the state is largely limited to erosional dissection of ancient alluvial plains. While many soil series within Louisiana display well-developed diagnostic horizons and features, other soils (either younger or more highly leached) have limited horizon development, which are far more nondescript and oft en classifi ed as Entisols or Inceptisols. For instance, the Roxana soil series (coarse-silty, mixed, superactive, nonacid, thermic Typic Udifl uvent) contains no diagnostic horizons or features. Th e Commerce soil series (fi ne-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquept) contains only a cambic horizon and ochric epipedon.

No abstract

No abstract

Core Ideas Use of N‐fertilizers decreased AMF populations and P, Ca, and Mg concentrations. Conservation tillage and cover crops increased C, N, and S cycling enzymes. Grass and brassica cover crops increased microbial populations compared to legumes. Agricultural production in the US Mid‐South has relied on frequent tillage and synthetic fertilizers decreasing soil health and system sustainability. Conservation tillage and cover crops can fill a vital role in reducing soil erosion while improving ecosystem functions. Seven cover crop blocks, including four legumes (berseem clover [Trifolium alexandrinum], crimson clover [Trifolium incarnatum L.], winter pea [Pisium sativum L.], and hairy vetch [Vicia villosa Roth], three grass & brassica (cereal rye [Secale cereale], forage radish [Raphanus sativus var. longipinnatus], and a cereal rye–forage radish mix), and one fallow control were established in northeast Louisiana to examine the influence of cover crop and urea fertilizer application rates (0, 235, 268, 302 kg N ha−1) on corn production and soil health under conservation tillage. Soil health indicators were measured each year following corn harvest and cover crop termination. The combination of cover crops and conservation tillage increased C and N enzyme activity over the 2 yr while arylsulfatase increased in the spring following cover crop termination only. Relative abundance of saprophytic fungi tended to be higher in legume plots compared to grass & brassica treatments. Overall, the application of N fertilizer at rates of 235 kg N ha−1 or higher decreased populations of AMF and concentrations of P, K, Ca, and Mg, but increased populations of Gram‐positive bacteria. The use of grass & brassica cover crops promoted K, S, Ca, and Mg availability, and supported greater abundance of total FAMEs and all FAME biomarkers except for saprophytic fungi.

Core Ideas Combination of cover crops with conservation tillage increased soil C. Cover crops significantly reduced nitrate‐N levels during the fallow season. Legume cover crops reduced N requirements when compared with non‐legumes. Conventionally managed, continuous monoculture row‐crop production has depleted the soil of nutrients, organic matter, and overall productivity. This has increased the need for external inputs, specifically N, to meet crop demand. Despite the growing interest in conservation practices, including minimal tillage and cover crops, little work has been reported in the Mid‐South region. Cereal rye (Secale cereal L.), forage radish (Raphanus sativus var. longipinnatus L.), berseem clover (Trifolium alexandrinum L.), crimson clover (Trifolium incarnatum L), winter pea (Pisium sativum L), hairy vetch (Vicia villosa Roth), and a cereal rye–forage radish mix were seeded in discrete blocks in October 2014, 2015, and 2016 along with a non‐cover fallow. Each block was divided into 16 sub‐plots to which one of four N fertilizer rates (0, 235, 268, and 302 kg N ha−1) were applied. Corn (Zea mays L.) grain yields increased with additions of N fertilizer; however, no difference was observed between the three fertilizer rates in 2 of 3 yr. Cover crops aided in the uptake and recycling of inorganic N, potentially reducing losses and providing N for subsequent cash crops. Following legume cover crops, corn grain yields were maximized with the addition of 235 kg N ha−1. Inclusion of grass and brassicas with no additional N input reduced corn grain yield, which remained lower than yield measured following legumes up to the 302 kg N ha−1 rate. Secondary benefits of cover crops included increased soil C (36%) and N (22%), and N cycling over a 2‐yr period.